1. Technical Field
This invention relates generally to a method and apparatus for efficient drying of materials. More specifically, it relates to an apparatus and method for drying yard waste so as to effect a more efficient utilization of this waste, such as for animal feed or the like. This provides an efficient and cost effective alternative disposition of such waste as contrasted with conventional methods such as landfills. The apparatus is well suited for drying numerous types of bulky materials such as citrus peels, potpourri, wood chips or hay in addition to grass clippings or other yard waste.
The average county landfill in Iowa takes in over 2,000 tons of yard waste annually. Yard waste consists mainly of leaves (approximately 30%) which are usable for bedding or sheep maintenance diets, lawn clippings (60%) which are usable for main diet, and miscellaneous (10%) such as garden vines and twigs which have questionable usage.
Generally, whereas alfalfa hay contains approximately 20% protein, lawn clippings contain approximately 27% average protein. Additionally, the lawn clippings are very palatable and digestible to sheep. Low weather stressed lawn clippings, such as spring or fall clippings, normally will have highest protein and total digestible nutrients (TDN) value and should be fed at most appropriate time, e.g., during lactation as contrasted with maintenance.
The range of yields in pounds of 72% moisture lawn clippings are approximately: 3,000 to 8,000 for dry (non-irrigated) land; 6,500 to 10,000 for irrigated land, and 10,000 to 14,000 for intensively managed (fertilized, irrigated) land. Thus, a profitable and efficient use of such material could be found if a means were available to dry this material. The present invention provides this means.
In converting lawn clippings to animal feed, molds resulting from storage must be considered. Lawn care chemical residue should not be a major concern. However, as a precaution, lawn clippings should not be fed to animals 14 days prior to slaughter. Excess urea fertilizer is toxic and should be kept in mind. Expected low levels and dilution with several lawns of material should eliminate the problem, as low levels are beneficial to digestion. Additionally, most molds originating in lawn grass or legume are not a problem since these are not toxic to ruminants.
As of 1976 there were 4 to 5 million acres worth of household lawns in the United States. Surely the amount has increased in both management and acres in the last 20 years. Each acre of land produces approximately 6,000 pounds of clippings a year. Consequently, these 5 million acres of land will produce approximately 30,000 billion lbs. of dry lawn clippings a year. This represents a potential of over 10 billion "ewe days" which would feed over 27 million ewes and accommodate total ewe hay needs for 55 thousand producers with herds of 500 head. If only 10% were salvageable, that amount would accommodate 5,500 500-head producers at a savings of 60 to 90 million dollars or approximately $24 to $36 per ewe.
The present invention has particular utility in or near urban areas where yard waste is being generated. This includes city municipalities, clubs active in recycling, zoos, animal feed and supply stores, lawn care services, golf courses, but most probably livestock producers. Other usable by-products include drying citrus peels and chopped alfalfa hay.
Yard waste constitutes 19% of the solid waste flow into United States landfills; that is approximately 35 million tons (1992 E.P.A. estimates). A federal mandate states solid waste is to be reduced an additional 25% from 1995 to the year 2000. Yard waste is a prime candidate for being banned from landfills. Present trends to reduce waste and recycle are aids in marketing our system.
2. Description of the Prior Art
Composting is the major, non landfill alternative to the present invention. However, according to many city recycling coordinators and composting operations, most are very open to other options. Of those surveyed, over 60% that had compost programs were unsatisfied with present composting programs and many of those that were satisfied were still very receptive to new or better alternatives. Composting is most often expensive and creates odor. Additionally, leaching of water from the site can cause pollution of streams and wells with nitrates, etc.
Several prior art dryers exist. However, none of these dryers has the simple vertical flow, taking advantage of the natural bridging action which occurs when lawn clippings are allowed to set.
One additional advantage of the drying apparatus of the present invention is the fact that it may be operated at low temperatures. In many cases, only ambient temperature air will be needed to accomplish the desired drying. Clearly, this makes the dryer apparatus of the present invention extremely efficient and economical since no energy need be expended in heating their air for the dryer. Additionally, low temperature systems obviously produce less heat-related damage. Most importantly, use of a lower temperature for drying of the material protects and preserves a greater quantity of the nutritionally significant elements in the material, resulting in a more valuable end product.
Therefore, it is a primary objective of the present invention is to develop a process and apparatus that would enable a sheep or other livestock producer to practically utilize lawn clippings as a feed source while significantly reducing his feed expense and thereby, making sheep and other livestock production more sustainable.
It is another objective of the present invention to provide a dryer utilizing low heat.
It is an additional objective to provide a dryer utilizing a simple vertical flow to channel the material from input to output.
It is another objective to utilize the bridging feature of the drying material to separate the drying material into a plurality of drying zones.
It is another objective to provide a dryer apparatus of a segmented construction wherein the volume of the dryer may be increased or decreased by adding or subtracting segments.